Mr Buck, who is wealthy, politically connected and white, has come under scrutiny over the overdose deaths, which involved “vulnerable” black men.

Los Angeles County District Attorney Jackie Lacey said on Tuesday she remains “deeply concerned for the safety of people whose life circumstances may make them more vulnerable to criminal predators”.

“With this new evidence, I authorised the filing of criminal charges against Ed Buck.”

Prosecutors have asked for bail to be set at $4m (£3m), calling Mr Buck a “violent, dangerous sexual predator” who targeted the homeless and those battling drug addiction.

Mr Buck, an LGBT activist who has donated tens of thousands of dollars to Democratic candidates, is expected in court on Wednesday. He could see a total of five years and eight months in state prison if convicted.

“From his home, in a position of power, Buck manipulates his victims into participating in his sexual fetishes,” prosecutors said in court documents.

“These fetishes include supplying and personally administering dangerously large doses of narcotics to his victims.”

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The latest alleged victim, who is 37 and remains unnamed, was allegedly injected with high doses of “meth” at Mr Buck’s apartment on 4 September, after which he sought medical attention.

He returned to the apartment on 11 September and was allegedly injected with meth again.

When the man believed he was overdosing, prosecutors say Mr Buck refused to help and “thwarted” his attempts to obtain assistance. The man allegedly fled and was able to call for help from a gas station.

What do we know about the two deaths?

In July 2017, 26-year-old Gemmel Moore died in Mr Buck’s apartment of a meth overdose. Mr Moore was found naked on a mattress, surrounded by drug paraphernalia and sex toys, officials said, and the death was initially ruled an accident.

Mr Moore had been homeless and worked as an escort, the Times reported.

After Mr Moore’s mother, LaTisha Nixon, questioned Mr Buck’s involvement in the overdose, an investigation was launched. But prosecutors later said they did not have enough evidence to charge Mr Buck.

Ms Nixon filed a wrongful death lawsuit against Mr Buck in February.

Her attorney, Hussain Turk, said in a statement: “If the dead body of a blond-haired, blue-eyed white man was found in the home of an older black man, he’d be lucky to even make it to the police station alive.”

A month earlier, 55-year-old Timothy Dean, a fashion consultant, was found dead of a meth overdose in the same apartment, prompting protests and demands for police to investigate.

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